This application claims the benefit of Korean Application No. 2000-22800, filed Apr. 28, 2000, in the Korean Industrial Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a plasma display panel, and more particularly, to an alternating-current (AC) type plasma display panel having improved partitions formed on a rear substrate of the panel.
2. Description of the Related Art
In general, a plasma display panel is a picture display device that provides desired figures, characters or graphics by injecting gases between two substrates having electrodes thereon, and exciting phosphors using ultraviolet (UV) rays generated by the discharged gases.
A plasma display panel is classified into a direct-current (DC) type and an alternating-current (AC) type according to the type of driving voltages applied to discharge cells (i.e., a discharge type) and is also classified into an opposite discharge type and a surface discharge type according to the arrangement type of electrodes.
A DC type plasma display panel is constructed such that all electrodes are exposed to a discharge space such that a migration of charges directly occurs between the corresponding electrodes. On the other hand, an AC type plasma display panel is constructed such that at least one electrode is covered by a dielectric layer, and there is no direct migration of charges between the corresponding electrodes. Instead, ions and electrons produced by the discharge adhere to the surface of the dielectric layer to form wall charges. In addition, sustained discharges (i.e., sustaining discharges) are allowed by a sustaining voltage.
In an opposite discharge plasma display panel, an address electrode and a scan electrode are opposed to each other at each unit pixel, and an addressing discharge and a sustaining discharge occur between the two electrodes. On the other hand, in a surface discharge plasma display panel, an address electrode, and common and scan electrodes, which correspond with the address electrode, are provided for each unit pixel to cause the addressing discharge and the sustaining discharge.
FIG. 1 illustrates a first conventional AC type plasma display panel 10. The plasma display panel 10 has a front substrate 11 and a rear substrate 12 opposed to and facing each other. Strip-shaped common electrodes 13 and strip-shaped scan electrodes 14 are alternately formed on a bottom surface of the front substrate 11. A bus electrode 15, which reduces the line resistance, is formed on a bottom surface of each of the common and scan electrodes 13 and 14. A first dielectric layer 16 is formed on a bottom surface of the front substrate 11 to cover the common electrodes 13, the scan electrodes 14, and the bus electrodes 15. A protective layer 17, such as a magnesium oxide (MgO), is formed on a bottom surface of the first dielectric layer 16.
Strip-shaped address electrodes 18 are formed on a top surface of the rear substrate 12 to be perpendicular with the common and scan electrodes 13 and 14. The address electrodes 18 are covered by a second dielectric layer 19. Strip-shaped partitions 100 are formed on the second dielectric layer 19 parallel with the address electrodes 18. Red (R), green (G) and blue (B) phosphor layers 110 are formed on the inner walls of the partitions 100.
In the conventional plasma display panel 10 having the aforementioned configuration, if a voltage is applied between the scan electrode 14 and the address electrode 18, a preliminary discharge occurs to fill wall charges therebetween. In such a state, if a voltage is applied to the common electrode 13 and the scan electrode 14, a glow discharge occurs to produce plasma, and (UV) rays generated by the plasma excite the phosphor layers 110, thereby implementing a picture image.
The partitions 100 may be formed on the rear substrate 12 by a screen printing method, a sandblast method, or a dry film method. However, since the partitions 100 have the phosphor layers 110 of different colors formed on the inner walls and bottoms thereof, the amount of phosphors coated per unit area is small.
To overcome the problem caused by the small amount of phosphors, alternative partitions have been proposed. FIG. 2 is a partially exploded diagram of a rear substrate 22 of a second conventional plasma display panel, and only the characteristic parts will be described herein.
Referring to FIG. 2, a plurality of address electrodes 28 are formed on the rear substrate 22. The address electrodes 22 are covered by a dielectric layer (not shown). A matrix-type partition 200 is formed on the dielectric layer. The partition 200 includes first partitions 201 formed parallel to the address electrodes 28, and second partitions 202 formed to be perpendicular with the address electrodes 28. Accordingly, the space for partitioning discharge cells is defined by the first and second partitions 201 and 202. R, G and B phosphor layers (not shown) are formed on the inner walls of the first and second partitions 201 and 202.
The partition 200 has an increased phosphor layer coating area compared to the partition 100 shown in FIG. 1, which advantageously improves the luminance. However, in performing a vacuum exhausting step for removing impurities containing residual moisture being inside the panel, it is very difficult to attain exhaustion due to a closed structure of the partition 200. Thus, the exhausting step is prolonged.
FIG. 3 is a partially exploded diagram of a rear substrate 32 of a plasma display panel, and only the characteristic parts will be described herein, like in FIG. 2. As shown, a plurality of address electrodes 38 are formed on the rear substrate 32. The address electrodes 38 may be covered by a dielectric layer (not shown). A plurality of meandering partitions 300 are formed on the dielectric layer to be parallel with the address electrodes 38. Since the area where phosphor layers (not shown) are coated is increased in the partitions 300, the luminance is somewhat improved during radiation of the light. However, since the partitions 300 are not of a strip shape, it is quite difficult to fabricate these partitions 300.
Also, since the spaces defining the R, G and B discharge cells are not positioned along a line, it is quite difficult to drive the plasma display panel using the partitions 300. Further, due to the meandering partitions 300, it is difficult to form a black matrix, which is formed in the boundary of adjacent discharge cells for the purpose of enhancing color purity on the front substrate, at a desired position.
Accordingly, it is an object of the present invention to provide an AC type plasma display panel which can improve the luminance of phosphors while maintaining color purity by improving the structure of partitions formed on a rear substrate of the panel to increase the area where phosphor layers are coated.
It is another object of the present invention to provide an AC type plasma display panel which can facilitate exhaustion and driving by improving the structure of partitions comprising strip-shaped main partitions and auxiliary partitions.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Accordingly, to achieve these and other objects, there is provided an AC type plasma display panel including a front substrate, a plurality of strip-shaped common and scan electrodes formed on a bottom surface of the front substrate, bus electrodes formed along one side of respective edges of the common and scan electrodes, a first dielectric layer formed on the bottom surface of the front substrate to cover the common and scan electrodes, a protective layer formed on the bottom surface of the first dielectric layer, a rear substrate opposite to and facing the front substrate, a plurality of address electrodes formed on a top surface of the rear substrate to be perpendicular with the common and scan electrodes, a second dielectric layer formed on the rear substrate to cover the address electrodes, partitions, including main partitions formed on the second dielectric layer in a strip-shape and a auxiliary partitions connected to the main partitions, to partition a discharge space, and R, G and B phosphor layers formed on inner walls of the partitions.
According to an aspect of the present invention, the main partitions are formed at an angle to the address electrodes.
According to another aspect of the present invention, the auxiliary partitions may include first auxiliary partitions extending from one side wall of each of the main partitions lengthwise, and a plurality of second auxiliary partitions extending from the other side wall of the main partition lengthwise, the first and second auxiliary partitions being substantially perpendicular with the main partitions.
According to yet another aspect of the present invention, the first and second auxiliary partitions alternate with each other such that the first auxiliary partitions extend from one side wall of the main partition, and the second auxiliary partitions extend from the opposing side wall of the next main partition.
According to a further aspect of the present invention, the main partitions are formed parallel with the address electrodes.
According to a still further aspect of the present invention, the plurality of auxiliary partitions are formed extending from one side wall of each of the main partitions lengthwise, and are formed substantially perpendicular with the main partitions.
According to an additional aspect of the present invention the auxiliary partitions may be formed extending from one side wall of each of the main partitions and are oriented in a same direction.
According to another aspect of the present invention, the auxiliary partitions include a plurality of first auxiliary partitions extending from one side wall of each of the main partitions lengthwise, and second auxiliary partitions extending from an other side wall of the main partition lengthwise.
According to another aspect of the present invention, auxiliary partitions are formed on the main partitions lengthwise only at the regions where the B phosphor layers are formed.
According to another aspect of the present invention, phosphor layers are further formed extending from outer side walls of the auxiliary partitions.
According to another aspect of the present invention, the auxiliary partitions may be integrally formed on the side walls of the main partitions and have a length to provide a space between facing side walls of two neighboring main partitions.